Patent Literature 1 discloses an example of microphone arrays of the type described above. According to Patent Literature 1, a microphone array includes a plurality of microphone devices arranged in array at appropriate intervals. A sound source position estimating function for estimating the position of a sound source is realized on the basis of audio signals outputted from the respective microphone devices, or, more specifically, three, in total, microphone devices, which are microphone devices at opposite ends of the array and a centrally disposed microphone device. Predetermined processing, including delay processing, is provided for the audio signals from the respective microphone devices to realize a relatively sharp directivity of the whole microphone array. In addition, a directivity's tracking function is provided to appropriately adjust the amounts of delay to be provided for the respective audio signals whereby the directivity can track the position of the sound source estimated by the sound source position estimating function.